El, Cigdem, and Mehmet Emin Celikkaya. β€œIs There a Predictive Association Between Vitamin D Concentrations and Lower Respiratory Tract Infections in Infants?”. Annals of Medical Research 26, no. 2 (February 23, 2019): 0289–0292. Accessed May 19, 2024. http://www.annalsmedres.org/index.php/aomr/article/view/4036.